The past decade has seen a resurgence of interest in the molecular defects underlying macular dystrophies. Firstly, this is because these diseases are important causes of incurable blindness and, secondly, the molecular defects highlighted by these studies may be relevant to the much commoner disease, age related macular degeneration (AMD). In this issue, Assink et al (p 682) have undertaken a molecular genetic study of one of these macular dystrophies: Sorsby's fundus dystrophy (SFD), an important addition to the literature, which also raises new questions.

The scientific literature describes SFD as a fully penetrant, autosomal dominant, retinal disease first described by Sorsby in 1949.1 Clinically, early, mid-peripheral, drusen2 and colour vision deficits are found.3 Some patients complain of night blindness.4 Most commonly, the presenting symptom is sudden acuity loss, manifest in the third to fourth decades of life, due to untreatable submacular neovascularisation.5Histologically, there is accumulation of a confluent lipid containing material 30 μm thick at the level of Bruch's membrane.

Parametric linkage …